On a multilayer circuit board, a semiconductor integrated circuit chip is mounted. With a conventional manufacturing technique, the spacing interval (pitch) between pads on a multilayer circuit board could not be as narrow as the pitch of terminal electrodes of a semiconductor integrated circuit chip. Therefore, in general, a semiconductor integrated circuit chip has been positioned on a multilayer circuit board with its terminal electrode side facing up, and the semiconductor integrated circuit chip and the pads of the multilayer circuit board have been connected to each other by wire bonding.
Nevertheless, in recent years, there has been a breakthrough in an alignment technique using a photoresist, a laser drill and the like, enabling the spacing interval between pads on a multilayer circuit board to be as narrow as the pitch of terminal electrodes of a semiconductor integrated circuit chip. Hence, flip-chip mounting has been used for connection of terminal electrodes of a semiconductor integrated circuit chip and pads on a multilayer circuit board. Where flip-chip mounting is used, terminal electrodes of a semiconductor integrated circuit chip are formed into bumps, and the semiconductor integrated circuit chip is placed on a multilayer circuit board with its terminal electrode side facing down, so that the terminal electrodes of the semiconductor integrated circuit chip and the pads of the multilayer circuit board are connected to each other directly. Therefore, wire bonding is no longer needed.
However, it is difficult to obtain highly precise positioning of a semiconductor integrated circuit chip onto a multilayer circuit board. One method for connecting terminal electrodes and pads despite some misalignment of a semiconductor integrated circuit chip is, for example, to increase the size of pads. However, since the spacing interval between the pads is small, this method has its limits.
Meanwhile, circuit elements such as a resistor and a capacitor are also mounted on a multilayer circuit board. As far as voltage drop, parasitic capacitance, noise, signal propagation speed and the like are concerned, it is preferred that these circuit elements be placed as close to a semiconductor integrated circuit chip as possible. However, there is also a limitation with respect to this.
Therefore there is a need to provide a multilayer circuit board that easily enables flip-chip mounting of an integrated circuit chip, and overcomes the limitations discussed above.